String creation and literal types in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this string literal code?

Consider the following C# code snippet. What will be printed to the console?

C Sharp (C#)

string path = @"C:\Users\Admin\Documents";
Console.WriteLine(path);

A C:\\Users\\Admin\\Documents

B C:\Users\Admin\Documents

C C:/Users/Admin/Documents

D C:UsersAdminDocuments

💡 Hint

Look at how the @ symbol affects backslashes in string literals.

The @ symbol before the string makes it a verbatim string literal, so backslashes are treated as normal characters and do not need to be escaped. Thus, the output shows single backslashes.

❓ Predict Output

intermediate

What does this string interpolation print?

Given the code below, what is the output?

C Sharp (C#)

int x = 5;
int y = 10;
string result = $"Sum of {x} and {y} is {x + y}";
Console.WriteLine(result);

A Sum of 5 and 10 is 15

B Sum of x and y is x + y

C Sum of {x} and {y} is {x + y}

D Sum of 5 and 10 is x + y

💡 Hint

Remember how variables inside $"..." strings are evaluated.

The $ symbol before the string allows expressions inside braces to be evaluated and inserted into the string. So {x} becomes 5, {y} becomes 10, and {x + y} becomes 15.

🔧 Debug

advanced

What error does this code raise?

Examine the following code. What error will occur when compiling or running it?

C Sharp (C#)

string s = "Hello\nWorld";
Console.WriteLine(s);

A Output: Hello (newline) World

B RuntimeException: Newline not allowed in string

C SyntaxError: Invalid escape sequence

D Compile-time error: Unterminated string literal

💡 Hint

Check how escape sequences like \n work in C# strings.

The \n is a valid escape sequence representing a newline character. The string prints Hello, then a newline, then World.

🧠 Conceptual

advanced

How many characters does this string contain?

What is the length of the string created by this code? string s = @"Line1\nLine2";

A 11

B 9

C 10

D 12

💡 Hint

Remember that verbatim strings treat backslashes as normal characters.

The string is verbatim, so \n is two characters: a backslash and an 'n'. Counting all characters: L i n e 1 \ n L i n e 2 = 12 characters.

❓ Predict Output

expert

What is the output of this complex string creation?

Analyze the code and determine what is printed:

C Sharp (C#)

string s = $@"Path: C:\Users\{Environment.UserName}\Documents";
Console.WriteLine(s);

A Path: C:\Users\\Documents

B Path: C:\Users\{Environment.UserName}\Documents

C Path: C:\Users\Admin\Documents

D Path: C:Users{Environment.UserName}Documents

💡 Hint

The string uses both $ and @ symbols. Consider how interpolation and verbatim strings combine.

The $@ combination means the string is verbatim and interpolated. Backslashes are literal, and expressions inside braces are evaluated. Environment.UserName is replaced by the current user name, e.g., Admin.

Practice

1. Which of the following correctly creates a string literal in C#?

easy

A. string s = `Hello World`;

B. string s = 'Hello World';

C. string s = Hello World;

D. string s = "Hello World";

Solution

1. Step 1: Understand string literal syntax in C#

   Strings in C# must be enclosed in double quotes (").

2. Step 2: Check each option for correct syntax

   string s = "Hello World"; uses double quotes correctly. string s = 'Hello World'; uses single quotes which are for characters, not strings. string s = Hello World; has no quotes, so it's invalid. string s = `Hello World`; uses backticks which are not valid string delimiters in C#.

3. Final Answer:

   string s = "Hello World"; -> Option D

4. Quick Check:

   Strings use double quotes = A [OK]

Hint: Strings always use double quotes in C# [OK]

Common Mistakes:

• Using single quotes for strings
• Omitting quotes around text
• Using backticks instead of quotes

2. Which of the following is the correct way to create a verbatim string literal in C#?

easy

A. string path = @"C:\Users\Admin";

B. string path = "C:\\Users\\Admin";

C. string path = 'C:\Users\Admin';

D. string path = `C:\Users\Admin`;

Solution

1. Step 1: Recall verbatim string syntax

   Verbatim strings start with @ and use double quotes, preserving backslashes as-is.

2. Step 2: Analyze each option

   string path = "C:\\Users\\Admin"; uses normal string with escaped backslashes. string path = @"C:\Users\Admin"; uses @ with double quotes correctly. string path = 'C:\Users\Admin'; uses single quotes which is invalid for strings. string path = `C:\Users\Admin`; uses backticks which are invalid.

3. Final Answer:

   string path = @"C:\Users\Admin"; -> Option A

4. Quick Check:

   Verbatim strings start with @ = A [OK]

Hint: Use @ before quotes for verbatim strings [OK]

Common Mistakes:

• Forgetting @ for verbatim strings
• Using single quotes for strings
• Not escaping backslashes in normal strings

3. What is the output of the following C# code?

string s = "Line1\nLine2";
Console.WriteLine(s);

medium

A. Line1\nLine2

B. Line1\n\nLine2

C. Line1
Line2

D. Line1 Line2

Solution

1. Step 1: Understand escape sequences in strings

   The sequence \n represents a newline character in C# strings.

2. Step 2: Predict output of Console.WriteLine

   The string "Line1\nLine2" will print as two lines: "Line1" on the first line and "Line2" on the second line.

3. Final Answer:

   Line1 Line2 -> Option C

4. Quick Check:

   \n creates new line = D [OK]

Hint: Escape \n prints new line in output [OK]

Common Mistakes:

• Printing \n literally instead of new line
• Confusing verbatim strings with normal strings
• Expecting spaces instead of new lines

4. Identify the error in this C# string declaration:

string s = @"Hello\nWorld";

medium

A. Escape sequences like \n are not processed in verbatim strings

B. No error, this is correct verbatim string

C. Backslash should be doubled as \\ in verbatim strings

D. Missing semicolon at the end

Solution

1. Step 1: Understand verbatim string behavior

   Verbatim strings treat backslashes literally and do not process escape sequences like \n.

2. Step 2: Analyze the given string

   The string @"Hello\nWorld" will contain the characters \ and n literally, not a newline.

3. Final Answer:

   Escape sequences like \n are not processed in verbatim strings -> Option A

4. Quick Check:

   Verbatim strings ignore escape sequences = B [OK]

Hint: Verbatim strings do not process escape sequences [OK]

Common Mistakes:

• Expecting \n to create new line in verbatim strings
• Doubling backslashes unnecessarily in verbatim strings
• Confusing normal and verbatim string rules

5. You want to create a string that contains the exact text:

C:\Users\Admin\Documents

Which of the following C# declarations will produce this exact string value?

hard

A. string path = "C:\Users\Admin\Documents";

B. string path = @"C:\Users\Admin\Documents";

C. string path = "C:\\Users\\Admin\\Documents";

D. string path = 'C:\Users\Admin\Documents';

Solution

1. Step 1: Understand how to represent backslashes in strings

   In normal strings, backslash is an escape character, so to represent one backslash, you must write \\.

2. Step 2: Check each option for resulting string

   string path = @"C:\Users\Admin\Documents"; uses verbatim string which preserves backslashes literally, producing the exact text with single backslashes. string path = 'C:\Users\Admin\Documents'; uses single quotes which is invalid for strings. string path = "C:\Users\Admin\Documents"; has single backslashes which are escape sequences and will produce the correct path string with single backslashes. string path = "C:\\Users\\Admin\\Documents"; doubles each backslash, resulting in double backslashes in the string, which is not the exact text.

3. Final Answer:

   string path = @"C:\Users\Admin\Documents"; -> Option B

4. Quick Check:

   Verbatim string preserves backslashes literally = D [OK]

Hint: Use verbatim string (@) to preserve backslashes literally [OK]

Common Mistakes:

• Using single quotes for strings
• Doubling backslashes unnecessarily in verbatim strings
• Confusing verbatim and normal string rules